This invention broadly relates to optical imaging. More particularly, however, the present invention concerns an optical display apparatus that may be employed to create a real image in space which real image may be viewed by an observer. The present invention particularly concerns an apparatus that produces a real image of an object but that prevents view of the object itself.
A variety of devices have been used in past to create images in space. In such devices, a variety of mirrors have been used to project an image of object so it appears that the object is at a location where it is not. Naturally, such devices can be used to present dramatic advertising effects.
An example of such an optical display device is shown is U.S. Pat. No. 5,111,357 issued May 10, 1994 to Summer et al. In the ""357 patent, a pair of concave mirrors are placed in a clam-shell configuration, so that the virtual image created by one mirror is reflected by the other mirror to create a real image that projects at least partially out of a view opening. In another embodiment of this invention, two mirrors are parallel to one another but are staggered to create the same effect.
In U.S. Pat. No. 4,802,750 issued Feb. 7, 1989 to Welck, a real image projection system again employs a clam-shell configuration of two facing curvilinear mirrors. Alternatively, one of the mirrors can be replaced by a reflective surface that creates a reflection of the other mirror to provide a curvilinear virtual reflective expanse. Each mirror has its vertex coincident with the focal point of the other mirror.
The disadvantage of the prior art optical imaging devices resides in the location of the object relative to the viewing opening. Typically, the object must be placed between the median planes of the mirrors (as defined by the planes containing their respective peripheral edges) or otherwise projected to a location between the median planes between the mirrors. In so doing, it is possible for an observer located exteriorly of the projection system to see the actual object through the view opening. This detracts from the overall appearance and effectiveness of the display.
It is an object of the present invention to provide an improved optical imaging apparatus where in an image of an object is projected either in or through a viewing area while at the same time the object itself is masked from view.
It is another object of the present invention to provide an improved optical system that enhances the clarity of a real image projected from an object.
According to the present invention, then, an image projecting apparatus whereby an observer located exteriorly of the image projecting apparatus can see an image of an object placed therein. Broadly, the imaging projecting apparatus according to the present invention includes a housing that defines an enclosure. The housing has an interior and an object support area that is adapted to receive an object to be displayed. The housing has a front portion having a view region viewable by an observer located exteriorly of the housing.
A concave first reflective surface is disposed in the housing and is oriented to receive light from the object and is operative to produce a virtual image of the object when the object is placed on this object support area. A second reflective surface is also disposed in the housing. The second reflective surface is oriented to reflect the virtual image produced by the first reflective surface as a real image of the object. The second reflective surface projects the real image into the view area. A masking member is also disposed in the housing and is interposed between the object support area of the view region such that the object cannot be viewed directly through the view region by the observer.
The first reflective surface defines a curvilinear surface area that can be selected from a group consisting of spiracle surfaces, parabolic surfaces, cylindrical surfaces and double cylindrical surfaces. Preferably, these reflective surfaces are sections of geometric shells of geometric shapes described above. The second reflective surface can take any of these same shapes but can also be a planar reflective surface, i.e., a planar mirror.
In the preferred invention, a light source is disposed in the interior of the housing and is located to illuminate an object placed on the object support area. To this end, also, a baffle panel may be disposed in the housing and positioned to prevent direct view of the light source by the observer. An opaque shroud may be employed and may be disposed in the interior of the housing to surround the view region in order to isolate the view region from that portion of the housing interior located outside of the housing. The shroud has an opening oriented such that the real image is projected through the opening and into the view region.
The masking member may be a suitable sized and positioned panel or, alternatively, may be defined by the second reflective surface. In order to allow the displayed object to be changed, an access panel is provided to the housing interior with this access panel being movable between open and closed position.
Preferably, the first reflective surface has a first peripheral edge, a first median plane containing the first peripheral edge and a center. Likewise, the second reflective surface has a second peripheral edge, a second median plane containing the second peripheral edge and a center. The first median plane is preferably oriented at an acute angle with respect to the second median plane, with this angle being in a range of about 25xc2x0 to 80xc2x0, inclusive. The center of the first reflective surface is offset rearwardly of the center of the second reflective surface, and a portion of the first reflective surface is preferably rearwardly offset from a rear portion of the second peripheral edge. The object support area is located within a geometric projection of the second peripheral edge and behind the second reflective surface.
Preferably, the image projecting apparatus is adapted to be supported on a support surface. The housing is such that the second median plane may be oriented at an angle of 0xc2x0 to 20xc2x0 with respect to a horizontal plane with the first and second reflective surfaces being suitably supported by the housing for their relative orientation to the horizontal plane and to each other. Thus, the first and second median planes are preferably oriented at an angle of about 25xc2x0 to 40xc2x0 with respect to one another. With this configuration, the first reflective surface is located at the back of the housing and reflects light forwardly and downwardly therein while the second mirror is located forwardly in the housing and reflects light from the first mirror upwardly and forwardly into the view.
These and other objects of the present invention will become more readily appreciated and understood from a consideration of the following detailed description of the exemplary embodiment(s) when taken together with the accompanying drawings, in which: